Help, Please!!! Can't Send Mail with SmtpClient

Hi, my jsp page uses sun.net.smtp.SmtpClient to send email. It worked fine until the hosted location was moved to another server. Now it generates the sun.net.smtp.SmtpProtocolException and the hosting company can't find what's wrong with it so I'm here hoping somebody can help.

The hosting company tried sending email from the server and it was okay and found no restrictions that prevents my page to access the smtp server.

What could cause the SmtpProtocolException? "locahost" was what I used to connect to the smtp server. When it failed, I tried another smtp server like "mail.xxx.com" for another domain and it worked but the problem is that this server can't let me send mail to other domains except its own domain.

sun.net.smtp.SmtpProtocolException:
at sun.net.smtp.SmtpClient.issueCommand(SmtpClient.ja va:48)
at sun.net.smtp.SmtpClient.closeServer(SmtpClient.jav a:38)
at sun.net.NetworkClient.openServer(NetworkClient.jav a:117)
at sun.net.smtp.SmtpClient.openServer(SmtpClient.java :111)
at sun.net.smtp.SmtpClient.(SmtpClient.java:156)
at org.apache.jsp.dbg.email_005fpass2_jsp._jspService (email_005fpass2_jsp.java:134)
at org.apache.jasper.runtime.HttpJspBase.service(Http JspBase.java:133)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:856)
at org.apache.jasper.servlet.JspServletWrapper.servic e(JspServletWrapper.java:311)
at org.apache.jasper.servlet.JspServlet.serviceJspFil e(JspServlet.java:301)
at org.apache.jasper.servlet.JspServlet.service(JspSe rvlet.java:248)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:856)
at org.apache.catalina.core.ApplicationFilterChain.in ternalDoFilter(ApplicationFilterChain.java:284)
at org.apache.catalina.core.ApplicationFilterChain.do Filter(ApplicationFilterChain.java:204)
at org.apache.catalina.core.StandardWrapperValve.invo ke(StandardWrapperValve.java:256)
at org.apache.catalina.core.StandardValveContext.invo keNext(StandardValveContext.java:151)
at org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:564)
at org.apache.catalina.core.StandardContextValve.invo keInternal(StandardContextValve.java:245)
at org.apache.catalina.core.StandardContextValve.invo ke(StandardContextValve.java:199)
at org.apache.catalina.core.StandardValveContext.invo keNext(StandardValveContext.java:151)
at org.apache.catalina.authenticator.AuthenticatorBas e.invoke(AuthenticatorBase.java:509)
at org.apache.catalina.core.StandardValveContext.invo keNext(StandardValveContext.java:149)
at org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:564)
at org.apache.catalina.core.StandardHostValve.invoke( StandardHostValve.java:195)
at org.apache.catalina.core.StandardValveContext.invo keNext(StandardValveContext.java:151)
at org.apache.catalina.valves.ErrorReportValve.invoke (ErrorReportValve.java:164)
at org.apache.catalina.core.StandardValveContext.invo keNext(StandardValveContext.java:149)
at org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:564)
at org.apache.catalina.core.StandardEngineValve.invok e(StandardEngineValve.java:156)
at org.apache.catalina.core.StandardValveContext.invo keNext(StandardValveContext.java:151)
at org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:564)
at org.apache.catalina.core.ContainerBase.invoke(Cont ainerBase.java:972)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(Co yoteAdapter.java:211)
at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyo teHandler.java:309)
at org.apache.jk.common.HandlerRequest.invoke(Handler Request.java:387)
at org.apache.jk.common.ChannelSocket.invoke(ChannelS ocket.java:673)
at org.apache.jk.common.ChannelSocket.processConnecti on(ChannelSocket.java:615)
at org.apache.jk.common.SocketConnection.runIt(Channe lSocket.java:786)
at org.apache.tomcat.util.threads.ThreadPool$ControlR unnable.run(ThreadPool.java:677)
at java.lang.Thread.run(Thread.java:536)